1. Field
The present invention relates to a rotary compressor, and, more particularly, to a rotary compressor, which can improve the sealing effect of a compressing chamber and minimize the introduction of a refrigerant or oil into the compressing chamber while an idling-rotation operation is performed in the compressing chamber.
2. Description of the Related Art
Korean Patent Registration No. 10-0621026 (published on Sep. 15, 2006) discloses a multiple rotary compressor comprising: an upper first compressing chamber and a lower second compressing chamber separated from each other; and first and second rollers rotating in the respective compressing chambers to perform a compressing operation in the compressing chambers, respectively. The conventional rotary compressor further includes: a first vane to divide the upper first compressing chamber; a second vane to divide the lower second compressing chamber; and a vane control device to selectively restrict or release the second vane, for achieving a variable compression capacity.
The vane control device restricts the second vane by applying a suction pressure into a back-pressure space defined by the second vane, or reciprocates the second vane by applying a discharge pressure into the back-pressure space. By controlling the operation of the second vane as described above, the vane control device causes a compressing-rotation operation or idling-rotation operation in the second compressing chamber, so as to achieve a variation in compression capacity.
However, in the above described conventional rotary compressor, when the first compressing chamber performs a compressing-rotation operation and the second compressing chamber performs an idling-rotation operation, the inner pressure of the second compressing chamber is lower than the inner pressure of a hermetic container, therefore a liquid mixture of compressed refrigerant and oil inside the hermetic container may be unintentionally introduced into the second compressing chamber. Specifically, the liquid mixture of compressed refrigerant and oil may be introduced into the second compressing chamber through gaps defined at upper and lower ends of the second roller. Once the liquid mixture of compressed refrigerant and oil is introduced into the second compressing chamber, it acts as a rotation load, and may result in deterioration in the efficiency of the compressor. Furthermore, while the respective compressing chambers perform a compressing-rotation operation, a compressed refrigerant gas may leak through the gaps defined at the upper and lower ends of the respective rollers, therefore the above described rotary compressor may have deterioration in compression efficiency.